A typical wireless communication system comprises a central controller, a plurality of base stations which transceive communication resources, and a plurality of communication units. A communication unit may be a portable radio, a mobile vehicle radio, a portable cellular telephone, and/or a data transmission unit. In addition, a communication resource may be a frequency, a frequency pair, a TDM time slot or another type of modulated signal carrier. When a substantial number of communication units have data to transmit to a target, where a target could be another communication unit or the central controller, a typical communication system polls the communication units to control the transmission of data.
A typical polling sequence comprises the central controller prompting each of the communication units sequentially and allocating them a predetermined period of time to transmit their data. This approach requires a substantial amount of data signals to be conveyed on a communication resource between the central controller and communication units, thereby reducing the overall efficiency of the communication system.
Another type of polling gives priority to specific events such as emergency conditions. In a priority polling scheme the central controller periodically transmits an indicator that a priority data time slot is upcoming. If a communication unit has priority data, it transmits the priority data to the central controller in response to the prompting. This improves time response for priority data in a polling sequence, however, it still requires a substantial amount of communication on a control channel between the central controller and the communication units to prompt the communication units to transmit their data.
Therefore, a need exists for a method that allows the communication units to sequentially transmit their data in an organized manner and to reduce communication on a control channel between the central controller and the communication unit.